From: Thomas Hellstrom Date: Wed, 12 Mar 2014 09:41:32 +0000 (+0100) Subject: drm/ttm: Work around performance regression with VM_PFNMAP X-Git-Tag: v3.14-rc7~8^2^2~1 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0e6d6ec02f867fe8d1f785312b7343b21052322f;p=pandora-kernel.git drm/ttm: Work around performance regression with VM_PFNMAP A performance regression was introduced in TTM in linux 3.13 when we started using VM_PFNMAP for shared mappings. In theory this should've been faster due to less page book-keeping but it appears like VM_PFNMAP + x86 PAT + write-combine is a particularly cpu-hungry combination, as seen by largely increased cpu-usage on r200 GL video playback. Until we've sorted out why, revert to always use VM_MIXEDMAP. Reference: freedesktop.org bugzilla bug #75719 Reported-and-tested-by: Acked-by: Alex Deucher Signed-off-by: Thomas Hellstrom Cc: stable@vger.kernel.org --- Reading git-diff-tree failed